Steroid Shots Ease Carpal Tunnel

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Patients with carpal tunnel syndrome reported fewer symptoms several months after receiving steroid injections, but most still opted for surgery within a year to relieve persistent pain.

Note that the study suggests that steroid injections provided short-term relief of carpal tunnel pain, but did not result in long-term symptom relief in the majority of patients.

Patients with carpal tunnel syndrome reported fewer symptoms several months after receiving steroid injections, but most still opted for surgery within a year to relieve persistent pain, researchers said.

Improvements in carpal tunnel severity scores 10 weeks after initial treatment were greater among patients who received 80 or 40 mg injections of methylprednisolone than in those given placebo injections, with a 0.64-point decrease in the high-dose group (95% CI -1.06-minus 0.21, P=0.003) and a 0.88-point decrease with the lower dose (95% CI -1.30-minus 0.46, P<0.001), according to Isam Atroshi, MD, of Hässleholm Hospital in Hässleholm, Sweden, and colleagues.

But these improvements failed to prevent most patients from requiring surgery soon after, the researchers reported in the Sept. 3 issue of the Annals of Internal Medicine. At evaluation 1 year after the injections, surgery rates were 73%, 81% and 92% in the 80-mg steroid, 40-mg steroid, and placebo groups, respectively.

These rates corresponded to a "modestly lower likelihood of surgery within 1 year after treatment" with steroids, they wrote.

The findings confirm that steroid injections provided short-term relief of carpal tunnel pain, but did not result in long-term symptom relief in the majority of patients, the researchers indicated.

"Future research should explore how to obtain a consistent durable effect," they wrote. "The goal is to find a medical treatment that effectively resolves carpal tunnel without the need to divide the transverse carpal ligament."

A recent survey of hand surgeons in the U.S. found that 80% reported using steroid injections to treat carpal tunnel, but very few randomized trials have examined the efficacy of the treatment. A 2009 systematic review concluded that steroid injections have a short-term benefit for the treatment of carpal tunnel, but the reviewers found just two high quality, randomized studies with a combined patient population of less than 150.

Neither of these trials followed patients long enough to provide evidence of sustained benefit and neither investigated possible dose-response relationships, Atroshi and colleagues noted.

To address these research shortcomings, the researchers randomized 111 patients into three equal groups to receive injections of either of the two doses of methylprednisolone or placebo.

All the participants had symptoms of classic or probable carpal tunnel (numbness or tingling in at least two of the four radial fingers) and all had been treated unsuccessfully with wrist splinting for two months.

In addition, their symptoms were severe enough to warrant referral for surgical consult. Patients with severe carpal tunnel, for which immediate surgery would typically be recommended, were not considered for the study. Other exclusion criteria included previous steroid injections, diabetes mellitus, thyroid disorder, inflammatory disease, polyneuropathy, pregnancy, and previous carpal tunnel release.

The study's primary endpoints were change in carpal tunnel symptom severity score at 10 weeks and the rate of surgery at 1 year. Secondary endpoints included time to surgery, change in carpal tunnel symptom severity score at 1 year, and treatment satisfaction at 10 weeks and 1 year.

Compared with patients who received placebo injections, those treated with 80 mg of methylprednisolone were less likely to have surgery (odds ratio 0.24, 95% CI 0.06-0.95, P=0.042), but no significant difference was seen between the 40-mg steroid and placebo groups.

Cox regression analysis with constant time showed that compared to the placebo group, the relative risk for surgery in the 80-mg methylprednisolone group was 0.79 (95% CI 0.64-0.99, P=0.039) and 0.88 (95% CI 0.73-1.06, P=0.180) for the 40-mg group.

Other findings included:

Time from injection to surgery was longer for the 80-mg (P=0.003) and 40-mg (P=0.022) groups relative to placebo.

At 10 weeks, both steroid groups had greater improvement than the placebo group in pain scores and higher treatment satisfaction (both P<0.025).

At 24 weeks and 1 year, there were no differences between the three groups in pain scores and treatment satisfaction (all P>0.100).

In an email exchange with MedPage Today, Atroshi noted that the findings should help physicians counsel their carpal tunnel patients about what they can and cannot expect from steroid treatments.

"The probability of a long-term benefit is relatively small, which should be taken into consideration by doctors who currently use this treatment on most of their patients," he wrote. "On the other hand, for doctors who rarely use it, our study shows that the treatment has a proven short-term benefit and therefore, in certain situations, could be an appropriate alternative to surgery."

The researchers received grant support from the Region of Scania Research and Development Foundation and Hassleholm Hospital Organization.

Study authors indicated they had no relevant financial interests.

Reviewed by Robert Jasmer, MD Associate Clinical Professor of Medicine, University of California, San Francisco and Dorothy Caputo, MA, BSN, RN, Nurse Planner

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